There are several moments during the episode when the fourth wall is broken. Firstly when Homer replies to Marge by saying "Lets put it to a vote America". This is in reference to the end of "The Nedliest Catch" where the country voted whether Ned and Edna should stay together. The fourth wall is broken again when Moe say the if a three act story is good enough for Aristotle, then its good enough for the Simpsons.
God last struck Homer with lightning as punishment in Pray Anything.
The last time Ned acted intolerant towards a moral woman's treatment of his children occurred in Bart Has Two Mommies.
The joke with the left gifted bidexterous and transhanded community's anagram is Lesbian, Gay, Bisexual and Transgender.
The chalkboard gag, "Call your mother during the commercials", refers to the episode's having originally aired on Mother's Day.
The thing inside the Scratchy costume in the video for Itchy & Scratchy weddings is obviously not a person.
Homer's tweet seen during the episode, "ARE YOU SUPPOSED TO EAT THOSE STICKERS ON APPLES? I’M GUESSING YES.", was tweeted by the real world Homer J. Simpson account during the episode's original broadcast.
This episode was previously known as "Ned 'n' Edna's Blend Agenda".
Someone greatly resembling Mr. Becker appears at Marge's party.
For the first time in an HD episode, Lisa's original "Simpsons Theme" sax solo is used.
In this episode, Rod and Todd are already students at the Onward Christian Schoolboys Academy, while Ned is opposed to them attending Springfield Elementary. However, Rod and Todd have made a few cameos at the school (including Lisa's band class), while Ned is a member of the PTA and has held Junior Campers meetings there.
Chazz Busby returns as the director of the passion play *Smoke on the Daughter "Everyone Loves Ned Flanders", which plays during the closing credits, was previously used as the theme song for The Adventures of Ned Flanders in "The Front".
Ned's parents last appeared in "Hurricane Neddy".
Ned thinks that a talking dog is the work of the devil. In "Bart the Lover", Todd thinks that a talking dog is blasphemous.
In one scene, Lindsey Naegle was seen in the audience during the play. In another scene, she was one of the actresses.
The same thing happened to Hans Moleman. He was even seen in the audience and on the stage in the same time.
Marge's face error.
Rod and Todd tell Edna that they're not allowed to play Scrabble because "only God can make words". However, Ned was seen playing Scrabble alone in Alone Again, Natura-Diddily. And if he's really a devout Christian, then he can't have a double standard, because hypocrisy is a sin.
Edna pulls Rod and Todd out of a Christian school and puts them in Springfield Elementary. The Flanders family seems to act as that Rod and Todd are newcomers to Springfield Elementary, however, they have been seen at the school in previous episodes.
These previous school cameos are probably the goofs, not this one. Large crowd scenes like that usually have many cameos, often by people who wouldn't usually be in the scene.
In Fête Accompli, where there is a stand with videos of Extreme Weddings, in the middle there is a Zero-G wedding. Later on where Marge and Lisa look at the stand, Zero-G has been replaced with a video of an Itchy and Scratchy wedding, with the title of the video on the stand changing as well.
An employee could have changed the video and title.
Lisa and Marge could have looked at a different stand.
If the display was automated, the screen could simply have switched to showing a different wedding. This can be done using presentation software such as PowerPoint. However, the title changed as well.
In the scene where Marge is telling Helen about the canapes, her mouth disappears for a frame.
During the Passion Play, Hans Moleman is seen in the audience. He is then seen on a cross to the left of Homer.